pdf: Early out from CopyImage if there's nothing to copy.

pdf/draw_utils.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "pdf/draw_utils.h"
 
 #include <algorithm>
 #include <math.h>
 #include <vector>
 
@@ skipping 128 matching lines @@
 
   pp::Rect copy_rc(draw_rc);
   copy_rc.Offset(-gradient_rc.x(), -gradient_rc.y());
   AlphaBlend(gradient, copy_rc, image, draw_rc.point(), transparency);
 }
 
 void CopyImage(const pp::ImageData& src, const pp::Rect& src_rc,
                pp::ImageData* dest, const pp::Rect& dest_rc,
                bool stretch) {
   DCHECK(src_rc.width() <= dest_rc.width() &&
-      src_rc.height() <= dest_rc.height());
+         src_rc.height() <= dest_rc.height());
+  if (src_rc.IsEmpty())
+    return;
 
   const uint32_t* src_origin_pixel = src.GetAddr32(src_rc.point());
   uint32_t* dest_origin_pixel = dest->GetAddr32(dest_rc.point());
   if (stretch) {
     double x_ratio = static_cast<double>(src_rc.width()) / dest_rc.width();
     double y_ratio = static_cast<double>(src_rc.height()) / dest_rc.height();
     int32_t height = dest_rc.height();
     int32_t width = dest_rc.width();
     for (int32_t y = 0; y < height; ++y) {
       uint32_t* dest_pixel = dest_origin_pixel;
@@ skipping 157 matching lines @@
   PaintShadow(image, rc.Intersect(clip_rc), shadow_rc, matrix);
 
   // Fill right part.
   rc = pp::Rect(object_rc.right(), object_rc.y(),
                 shadow_rc.right() - object_rc.right(), object_rc.height());
   PaintShadow(image, rc.Intersect(clip_rc), shadow_rc, matrix);
 }
 
 }  // namespace chrome_pdf